Does a Postgres UNIQUE constraint imply an index?

问题

When adding a unique constraint to a Postgres table does that imply that an index has also been added to that table?

Meaning, if I add a UNIQUE constraint on a text column, does that text column now have an index or does an index have to be added separately?

回答1:

Yes. UNIQUE constraints are implemented using a btree index in Postgres.

Details:

• How does PostgreSQL enforce the UNIQUE constraint / what type of index does it use?

来源：https://stackoverflow.com/questions/29655439/does-a-postgres-unique-constraint-imply-an-index